After randomization of subfertile couples with an isolated cervical factor to intrauterine insemination for 6 months or expectant management for 6 months, 26 women (51%) vs. 16 women (33%) conceived, respectively. Of these pregnancies, 22 (43%) vs. 13 (27%) were ongoing (relative risk, 1.6; 95% confidence interval, 0.91 to 2.8). There was one multiple pregnancy in the group that was allocated to intrauterine insemination. This trial suggests a beneficial effect of IUI in couples with an isolated cervical factor.,
Fertility and Sterility
Erasmus MC: University Medical Center Rotterdam

Steures, P, van der Steeg, J.W, Hompes, P.G, Bossuyt, P.M.M, Habbema, J.D.F, Eijkemans, M.J.C, … Mol, B.W.J. (2007). Effectiveness of intrauterine insemination in subfertile couples with an isolated cervical factor: a randomized clinical trial. Fertility and Sterility, 88(6), 1692–1696. doi:10.1016/j.fertnstert.2007.01.124